This peptide is histone H4 amino acid residues 1 to 21. It is asymmetrically dimethylated at Arg3 with both methyl groups added to one nitrogen of the guanidinium group, and also contains a C-terminal GG linker, followed by a biotinylated Lys. Methylation of histone H4 at Arg3 is an important step in transcriptional activation, and allows for subsequent acetylation of H4 tails by p300. Provided at >95% peptide purity, this peptide was dissolved in distilled water at 1 mg/ml and re-lyophilized to powder form.